1. Field of the Invention
The present invention relates to a liquid crystal device applied to projection televisions, flat panel display systems, etc.
2. Related Background Art
In recent years, it is expected to accomplish a large-screen flat panel display system that utilizes high response and bistability inherent in ferroelectric liquid crystals (FLC).
Display panels making use of such ferroelectric liquid crystals (FLC) are comprised of a cell with a very small thickness usually of 1 .mu.m to 2 .mu.m, which is approximately 1/10 to 1/5 of that in TN (twisted nematic) type liquid crystal panels. Since a high voltage usually of about 27 V is used as a drive voltage at the time of selection, they also use as an insulating layer a sputter film formed of SiO.sub.2 or Ta.sub.2 O.sub.5, endurable to an electric field of as high as about 2.times.10.sup.7 V/m which is beyond comparison with that of the TN type liquid crystal panels.
As for methods of fabricating MIM devices provided in such liquid crystal panels, it has been hitherto well known to use anodic oxidation that can selectively oxidize a metal portion of the anode.
However, when the MIM devices are formed on such ferroelectric liquid crystal panels with the anodic oxidation method as mentioned above, the insulating layer at the part of liquid crystal has had to be formed using other process since only the metal portion is selectively oxidized.
In the sputter film formed of SiO.sub.2, Ta.sub.2 O.sub.5 or the like, pinholes may so frequently occur that the insulating film of MIM devices has been problematic in view of stability.
Thus, the ferroelectric liquid crystal devices having an MIM device have a high display quality level but on the other hand have had a disadvantage of high cost.
Faulty switching also has been found to occur at part of a ferroelectric liquid crystal layer when the layer is in a state in which a ferroelectric liquid crystal layer at a picture element area to which a voltage is applied and a ferroelectric liquid crystal layer located between picture elements, to which no voltage is applied, or at the area in which an MIM device is provided are adjoining. This faulty switching is caused by a peculiar polarized domain structure mainly resulting from the spontaneous polarization of a ferroelectric liquid crystal, and occurs more frequently when there is a greater difference in alignment between the ferroelectric liquid crystal layer at the picture element area and the ferroelectric liquid crystal layer at the non-picture element area.
The faulty switching is apt to unreasonably restrict design conditions such as driving voltage and driving frequency in matrix drive, and hence is undesirable for putting devices into practical use.